They're all essentially the same thing, with some minor differences. UAV is an acronym for "Unmanned Aerial Vehicle," UAS stands for "Unmanned Aerial System," and "Drone" stands for... well, a fully automated flying robot.

The sad thing is, the term "drone" often carries with it a negative connotation because it incorrectly refers to the unmanned military aircraft that carry out strikes. It also seems to be the term of choice for people who worry over privacy issues and people who believe that every drone out there is trying to spy on them (which is ridiculous - most peoples' lives aren't nearly interesting enough to warrant any kind of spying whatsoever).

The incorrectly-termed "drones" that carry out military strikes fall under the Unmanned Aerial Vehicle category. UAV's are flown from a remote location by a pilot, and the control inputs made by the UAV pilot at the ground station are converted into electronic signals which are sent to the aircraft in real time via radio or satellite.

Technically speaking, a "drone" is a machine that basically flies under a completely pre-programmed route. There is little to no control inputs done by a person because everything is pre-programmed before flight. Drones can be thought of as robotic multi-copters that have a set mission the same way a machine in an auto-assembly plant has a set mission to assemble cars.

An Unmanned Aerial Vehicle, and all of it's ground-based pilot control input systems and radios, is considered an Unmanned Aerial System, or UAS.

Hopefully this clears up some of the confusion. But now you may be asking, "if Southern Oregon Drone flies a "drone," why does a guy show up with a remote controller to fly it? It's not a drone because it has a pilot, so shouldn't it be called Southern Oregon UAV instead?"

You are correct. And once the general public begins to search the internet for "UAV photography" instead of "drone photography," we might just change to Southern Oregon UAV. But until that happens, we're going to stick with our marketing-friendly name :)